import numpy as np

a1 = np.array([1, 2, 3, 4])
# print(a1[2])
# print(a1[:2])

a2 = np.array([
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9]
])
# [7 8 9]
# print(a2[2])
# 8
# print(a2[2,1])
# [[1 2 3]
#  [4 5 6]]
# print(a2[:2])
a3 = np.array([
    [[10, 11, 12], [13, 14, 15], [16, 17, 18]],
    [[20, 21, 22], [23, 24, 25], [26, 27, 28]],
    [[30, 31, 32], [33, 34, 35], [36, 37, 38]]
])
# (3, 3, 3)
print(a3.shape)
# [[20 21 22]
#  [23 24 25]
#  [26 27 28]]
print(a3[1])